1. Field of the Invention
The invention relates to a storage cell connection for at least two storage cells based on alkali metal and chalcogen with each cell having at least one anode space and a cathode space which are separated from each other by an alkali ion-conducting solid electrolyte and are bounded at least in some regions by a metallic housing, as well as one first connecting element in electrical connection with a cathodic current collector and one second connecting element in electrical connection with an anodic current collector.
2. Description of the Prior Art
Rechargeable electrochemical storage cells with solid electrolytes are particularly suitable for construction of storage batteries having a high energy and power density. The solid electrolyte used in sodium-sulfur storage cells of beta aluminum oxide allows only sodium ions to pass. In contrast to the lead storage battery this means that practically no self-discharge takes place and no secondary reactions proceed during the charging, such as, for instance, water decomposition in lead-lead oxide systems. The current yield, i.e. the Faraday efficiency of such a sodium/sulfur storage cell is close to approximately 100%.
A multiplicity of such electrochemical storage cells are wired together for the manufacture of storage cells and high-temperature storage batteries. The high-temperature storage battery for an electric vehicle should, for instance, have an energy content of 40 kwh. If a total of 200 volts is to be generated with such a battery, about 500 storage cells must be wired together for the construction of the storage battery if it is assumed that each storage cell furnishes a voltage of about 2 volts.
Bus bars or cell jumpers which are made of and copper are used for the wiring, in particular the electrical connection of the storage cells to form such a battery. These bus bars and cell jumpers are protected against corrosion by plasma-injected aluminum or aluminum oxide layers. The connection of the storage cell to the bus bars or cell jumpers as well as the connection of the bus bars and cell jumpers among each other is accomplished by screws. It has been found that, due to the insufficient heat stability of copper, screw connections become loose and that this loosening cannot be prevented by the use of cup springs. Furthermore, an increased contact resistance is caused by the formation of oxide on the aluminum coating.
German DE-OS No. 30 33 117 discloses storage batteries in which cell jumpers or bus bars of aluminum clad steel or alloy steel connections are used for the wiring of the storage cells. However, here also, oxide formations occur which result in a large increase of the contact resistance.
The use of bus bars and cell jumpers of aluminum alloys, such as for instance, aluminum, copper, manganese alloys or aluminum magnesium alloys is likewise not suitable due to their low heat stability.